Bladder element formed from three sheets and method of manufacturing a bladder element

ABSTRACT

A method of manufacturing a bladder element comprises forming at least one of a first, a second, and a third polymeric sheet to have a contoured surface profile. The first, the second, and the third polymeric sheets are stacked so that the second polymeric sheet is between the first polymeric sheet and the third polymeric sheet. The method comprises applying fluid pressure between the first polymeric sheet and second polymeric sheet, between the second polymeric sheet and the third polymeric sheet, or between both, forcing a first surface of the second polymeric sheet into contact with an inner surface of the first polymeric sheet, or a second surface of the second polymeric sheet into contact with an inner surface of the third polymeric sheet, or both. A bladder element is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and is a National Stage entry ofInternational Patent Application No. PCT/US2016/028384, filed Apr. 20,2016, which claims the benefit under 35 U.S.C. 119(e) of priority toUnited States Provisional Application No. 62/150,507, filed Apr. 21,2015, and to United States Provisional Application No. 62/150,503, filedApr. 21, 2015, both of which are incorporated by reference in theirentirety.

TECHNICAL FIELD

The present teachings generally include a bladder element, and a methodof manufacturing a bladder element.

BACKGROUND

Footwear typically includes a sole configured to be located under awearer's foot to space the foot away from the ground or floor surface.Footwear sometimes utilizes polyurethane foam or other resilientmaterials in the sole to provide cushioning. A fluid-filled bladderelement is sometimes included in the sole to provide desired cushioning.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration in exploded perspective view of anembodiment of a bladder element for an article of footwear.

FIG. 2 is a schematic cross-sectional and fragmentary illustration inexploded view of a mold assembly and the bladder element of FIG. 1.

FIG. 3 is a schematic cross-sectional and fragmentary illustration ofthe mold assembly of FIG. 2 in a closed position forming the bladderelement of FIG. 1.

FIG. 4 is a schematic cross-sectional illustration of the bladderelement of FIG. 1 taken at lines 4-4 in FIG. 1.

FIG. 5 is a schematic illustration in side view of an embodiment of abladder element for an article of footwear, showing a footwear upperwith phantom lines, in accordance with an alternative embodiment of thepresent teachings.

FIG. 6 is a schematic cross-sectional illustration of the bladderelement of FIG. 5 taken at lines 6-6 in FIG. 5.

FIG. 7 is a schematic illustration in partially exploded side view of abladder element for an article of footwear in accordance with anotheralternative embodiment of the present teachings.

FIG. 8 is a schematic cross-sectional illustration of the bladderelement of FIG. 7 taken at lines 8-8 in FIG. 7.

FIG. 9 is a schematic illustration in partially exploded perspectiveview of the bladder element of FIGS. 7 and 8.

FIG. 10 is a schematic cross-sectional fragmentary illustration inclose-up view of a portion of a polymeric sheet of the bladder elementof FIG. 4.

FIG. 11 is a schematic illustration of a predetermined map of pressuresapplied during wear testing of an article of footwear such as any of thearticles of footwear of FIGS. 1-10.

DESCRIPTION

A method of manufacturing a bladder element comprises forming at leastone of a first polymeric sheet, a second polymeric sheet, or a thirdpolymeric sheet to have a contoured surface profile, and, after saidforming, stacking the first polymeric sheet, the second polymeric, andthe third polymeric sheet so that the second polymeric sheet is betweenthe first polymeric sheet and the third polymeric sheet. In anembodiment, the three polymeric sheets may be coextensive when stacked.

The method also comprises applying fluid pressure in the mold assemblybetween the first polymeric sheet and second polymeric sheet, forcing asecond surface of the second polymeric sheet into contact with an innersurface of the third polymeric sheet. Alternatively, or in addition, themethod may comprise applying fluid pressure between the second polymericsheet and the third polymeric sheet, forcing a first surface of thesecond polymeric sheet into contact with an inner surface of the firstpolymeric sheet.

Forming at least one of the first polymeric sheet, the second polymericsheet, or the third polymeric sheet to have a contoured surface profilemay comprise forming each of the first polymeric sheet, the secondpolymeric sheet, and the third polymeric sheet such that each of thefirst polymeric sheet, the second polymeric sheet, and the thirdpolymeric sheet have a respective contoured surface profile.

In one embodiment, forming at least one of the first polymeric sheet,the second polymeric sheet, or the third polymeric sheet to have acontoured surface profile is by thermoforming.

The method may comprise securing a flange at a perimeter of at least oneof the first polymeric sheet, the second polymeric sheet, or the thirdpolymeric sheet, to a flange at a perimeter of another of the firstpolymeric sheet, the second polymeric sheet, or the third polymericsheet by at least one of compression, radio-frequency welding, thermalbonding, or adhesive.

In an embodiment, forming at least one of the first polymeric sheet, thesecond polymeric sheet, or the third polymeric sheet configures thefirst polymeric sheet and the second polymeric sheet so that a firstfluid chamber comprises a volume bounded by the first polymeric sheetand the second polymeric sheet, and a second fluid chamber comprises avolume bounded by the second polymeric sheet and the third polymericsheet. In such an embodiment, the method may further comprise inflatingat least one of the first fluid chamber or the second fluid chamber. Forexample, if the first fluid chamber is isolated from the second fluidchamber, inflating at least one of the first fluid chamber or the secondfluid chamber may comprise inflating the first fluid chamber to a firstpredetermined pressure, and inflating the second fluid chamber to asecond predetermined pressure.

In an embodiment, forming at least one of the first polymeric sheet, thesecond polymeric sheet, or the third polymeric sheet to have a contouredsurface profile comprises configures the second polymeric sheet so thata third fluid chamber comprises a volume bounded by the first polymericsheet and the second polymeric sheet, and a fourth fluid chambercomprises a volume bounded by the second polymeric sheet and the thirdpolymeric sheet. In such an embodiment, the third fluid chamber and thefourth fluid chamber are isolated from the first fluid chamber, from thesecond fluid chamber, or from one another, and inflating also comprisesinflating the third fluid chamber to a third predetermined pressure, andthe fourth fluid chamber to a fourth predetermined pressure. At leastone of the first predetermined pressure, the second predeterminedpressure, the third predetermined pressure, and the fourth predeterminedpressure differs from another of the first predetermined pressure, thesecond predetermined pressure, the third predetermined pressure, and thefourth predetermined pressure.

The method may be used to manufacture a bladder element for an articleof footwear or a bladder element for a different application. In anembodiment, the bladder element is included in a sole assembly of anarticle of footwear, and the bladder element comprises at least one of aforefoot portion, a midfoot portion, and a heel portion. If oneembodiment in which the bladder element comprises a forefoot portion, amidfoot portion and a heel portion, the first fluid chamber extends overthe second fluid chamber in the heel portion, and the third fluidchamber and the fourth fluid chamber are adjacent one another in theforefoot portion. Accordingly, using only three polymeric sheets, thebladder element may have different fluid chambers with differentinflated pressures, and with the chambers layered above and below oneanother, and/or positioned side-by-side.

The method may further comprise monitoring pressures applied to anarticle of footwear during wear testing, and selecting at least some ofthe predetermined pressures based on the pressures applied. Stateddifferently, the predetermined inflation pressures of the chambers canbe based on population averages of wear testing data, or on specificwear testing data from a specific customer.

The method may comprise securing the first surface of the secondpolymeric sheet to the inner surface of the first polymeric sheet, andthe second surface of the second polymeric sheet to the inner surface ofthe third polymeric sheet while the second polymeric sheet, the firstpolymeric sheet, and the third polymeric sheet are in the mold assembly.The mold assembly may be a thermoforming and/or vacuuforming moldassembly, in which case the forming is thermoforming and/orvacuuforming. In one embodiment, the securing of the sheets isaccomplished with first polymeric sheet and the second polymeric sheetfree of anti-welding material, or with the second polymeric sheet andthe third polymeric sheet free of anti-welding material, or with thefirst polymeric sheet, the second polymeric sheet, and the thirdpolymeric sheet free of anti-welding material. By eliminating any stepof placing anti-welding material between the polymeric sheets, themanufacturing process is simplified.

In one embodiment, forming at least one of the first polymeric sheet,the second polymeric sheet, or the third polymeric sheet with acontoured surface profile comprises forming the second polymeric sheetwith the contoured surface profile. Securing the first surface of thesecond polymeric sheet to the inner surface of the first polymeric sheetand the second surface of the second polymeric sheet to the innersurface of the third polymeric sheet tethers the first polymeric sheetto the third polymeric sheet via the second polymeric sheet. Tetheringof the first and third polymeric sheets via the second polymeric sheetis at specific locations so that the fluid chambers defined by theadjacent sheets and bounded by the tethers are positioned to provide adesired cushioning response.

Forming at least one of the first polymeric sheet, the second polymericsheet, or the third polymeric sheet to have a contoured surface profilemay comprise forming each of the first polymeric sheet, the secondpolymeric sheet, and the third polymeric sheet with a respectivecontoured surface profile.

In an embodiment, forming at least one of the first polymeric sheet, thesecond polymeric sheet, or the third polymeric sheet with a contouredsurface profile comprises forming the third polymeric sheet with acavity comprising an open side. In such an embodiment, the secondpolymeric sheet extends into the cavity from the open side. For example,the first and second polymeric sheets may be secured to one anotherprior to stacking with the third polymeric sheet in the mold assembly,and the second polymeric sheet with its contoured surface profile isthen placed into the open cavity of the third polymeric sheet.

In an embodiment, forming at least one of the first polymeric sheet, thesecond polymeric sheet, or the third polymeric sheet with a contouredsurface profile comprises forming the second polymeric sheet so that thesecond polymeric sheet at least partially defines a plurality of fluidchambers between the first polymeric sheet and the third polymericsheet, and at least some of the plurality of fluid chambers are isolatedfrom one another by the second polymeric sheet.

A bladder element comprises a first polymeric sheet, a second polymericsheet, and a third polymeric sheet. At least one of the first, thesecond, and the third polymeric sheets is formed with a contouredsurface profile. The first, the second, and the third polymeric sheetsare stacked so that the second polymeric sheet is between the firstpolymeric sheet and the third polymeric sheet. A first surface of thesecond polymeric sheet may be in contact with an inner surface of thefirst polymeric sheet, or a second surface of the second polymeric sheetmay be in contact with an inner surface of the third polymeric sheet, orboth the first surface of the second polymeric sheet may be in contactwith an inner surface of the first polymeric sheet, and the secondsurface of the second polymeric sheet may be in contact with the innersurface of the third polymeric sheet. Pressurized fluid may be betweenthe first polymeric sheet and the second polymeric sheet, between thesecond polymeric sheet and the third polymeric sheet, or between thefirst polymeric sheet and the second polymeric sheet, and between thesecond polymeric sheet and the third polymeric sheet.

In an embodiment, the third polymeric sheet comprises a cavity with anopen side, and the second polymeric sheet extends into the cavity fromthe open side.

In an embodiment, the bladder element is a bladder element of an articleof footwear and comprises at least one of a forefoot portion, a midfootportion and a heel portion. For example, in an embodiment, the firstfluid chamber extends over the second fluid chamber in the heel portion,and the third fluid chamber and the fourth fluid chamber are adjacentone another in the forefoot portion.

In an embodiment, a first fluid chamber comprises a volume bounded bythe first polymeric sheet and the second polymeric sheet, and a secondfluid chamber comprises a volume bounded by the second polymeric sheetand the third polymeric sheet. The first fluid chamber is inflated to afirst predetermined pressure and the second fluid chamber is inflated toa second predetermined pressure. In such an embodiment, the secondpolymeric sheet may be configured so that a third fluid chambercomprises another volume bounded by the first polymeric sheet and thesecond polymeric sheet, and a fourth fluid chamber comprises anothervolume bounded by the second polymeric sheet and the third polymericsheet. The third fluid chamber and the fourth fluid chamber are isolatedfrom the first fluid chamber, from the second fluid chamber, or from oneanother. The third fluid chamber has a third predetermined pressure andthe fourth fluid chamber has a fourth predetermined pressure. At leastone of the first predetermined pressure, the second predeterminedpressure, the third predetermined pressure, and the fourth predeterminedpressure differs from another of the first predetermined pressure, thesecond predetermined pressure, the third predetermined pressure, and thefourth predetermined pressure.

In an embodiment, the second polymeric sheet is configured so that aplurality of fluid chambers comprise volumes bounded by the firstpolymeric sheet and the second polymeric sheet, or by the secondpolymeric sheet and the third polymeric sheet, and at least some of theplurality of fluid chambers are isolated from one another by the secondpolymeric sheet.

In an embodiment, at least one of the first polymeric sheet, the secondpolymeric sheet, or the third polymeric sheet comprises a multi-layerpolymeric sheet. For example, the multi-layer polymeric sheet may be aflexible micro-layer membrane that includes alternating layers of a gasbarrier polymer material and an elastomeric material. The layers mayinclude ethylene-vinyl alcohol copolymer, thermoplastic polyurethane,and a regrind material of the ethylene-vinyl alcohol copolymer andthermoplastic polyurethane.

In an embodiment, a bladder element comprises a first polymeric sheet, asecond polymeric sheet, and a third polymeric sheet. The first, thesecond, and the third polymeric sheets are stacked with the secondpolymeric sheet between the first polymeric sheet and the thirdpolymeric sheet. The second polymeric sheet has a contoured surfaceprofile and is secured to at least one of an inner surface of the firstpolymeric sheet or an inner surface of the third polymeric sheet so thata first fluid chamber comprises a volume bounded by the first polymericsheet and the second polymeric sheet, and a second fluid chambercomprises a volume bounded by the second polymeric sheet and the thirdpolymeric sheet. The first fluid chamber is isolated from the secondfluid chamber by the second polymeric sheet.

In an embodiment, the third polymeric sheet comprises a cavity with anopen side. The second polymeric sheet extends into the cavity from theopen side. For example, the second polymeric sheet may be entirely inthe cavity and enclosed therein by the first polymeric sheet and thethird polymeric sheet, and the first polymeric sheet may cover the openside.

The first polymeric sheet and the third polymeric sheet are relativelyflat in comparison to the contoured surface profile of the secondpolymeric sheet. In an embodiment, the first polymeric sheet, the secondpolymeric sheet, and the third polymeric sheet are relatively flat inthe heel portion in comparison to the contoured surface profile of thesecond polymeric sheet in the forefoot portion. For example, the firstpolymeric sheet and the third polymeric sheet may be relatively flat incomparison to the contoured surface profile of the second polymericsheet.

In one embodiment, the first and the third polymeric sheets are securedonly to the second polymeric sheet and not directly to one another. Forexample, the second polymeric sheet may be secured to the inner surfaceof the first polymeric sheet, and the second polymeric sheet may besecured to the inner surface of the third polymeric sheet.

In an embodiment, a first peripheral flange of the first polymeric sheetis secured to a second peripheral flange of the second polymeric sheet,and the second peripheral flange is secured to a third peripheral flangeof the third polymeric sheet. For example, in one embodiment, the firstperipheral flange, the second peripheral flange, and the thirdperipheral flange form a continuous peripheral flange that surrounds thebladder element. The contoured surface profile is between the continuousperipheral flange (i.e., laterally and longitudinally inward thereof),so that the second polymeric sheet is secured to the inner surface ofthe first polymeric sheet and/or the inner surface of the thirdpolymeric sheet laterally and longitudinally inward of the continuousperipheral flange.

In an embodiment, the first polymeric sheet and the second polymericsheet are free of anti-welding material, or the second polymeric sheetand the third polymeric sheet are free of anti-welding material, or thefirst polymeric sheet, the second polymeric sheet, and the thirdpolymeric sheet are free of anti-welding material. Stated differently,the first polymeric sheet is secured to the second polymeric sheetwithout anti-welding material between the first polymeric sheet and thesecond polymeric sheet, the second polymeric sheet is secured to thethird polymeric sheet without anti-welding material between the secondpolymeric sheet and the third polymeric sheet, or both the firstpolymeric sheet is secured to the second polymeric sheet withoutanti-welding material between the first polymeric sheet and the secondpolymeric sheet, and the second polymeric sheet is secured to the thirdpolymeric sheet without anti-welding material between the secondpolymeric sheet and the third polymeric sheet.

The above features and advantages and other features and advantages ofthe present teachings are readily apparent from the following detaileddescription of the modes for carrying out the present teachings whentaken in connection with the accompanying drawings.

“A,” “an,” “the,” “at least one,” and “one or more” are usedinterchangeably to indicate that at least one of the items is present. Aplurality of such items may be present unless the context clearlyindicates otherwise. All numerical values of parameters (e.g., ofquantities or conditions) in this specification, unless otherwiseindicated expressly or clearly in view of the context, including theappended claims, are to be understood as being modified in all instancesby the term “about” whether or not “about” actually appears before thenumerical value. “About” indicates that the stated numerical valueallows some slight imprecision (with some approach to exactness in thevalue; approximately or reasonably close to the value; nearly). If theimprecision provided by “about” is not otherwise understood in the artwith this ordinary meaning, then “about” as used herein indicates atleast variations that may arise from ordinary methods of measuring andusing such parameters. In addition, a disclosure of a range is to beunderstood as specifically disclosing all values and further dividedranges within the range. All references referred to are incorporatedherein in their entirety.

The terms “comprising,” “including,” and “having” are inclusive andtherefore specify the presence of stated features, steps, operations,elements, or components, but do not preclude the presence or addition ofone or more other features, steps, operations, elements, or components.Orders of steps, processes, and operations may be altered when possible,and additional or alternative steps may be employed. As used in thisspecification, the term “or” includes any one and all combinations ofthe associated listed items. The term “any of” is understood to includeany possible combination of referenced items, including “any one of” thereferenced items. The term “any of” is understood to include anypossible combination of referenced claims of the appended claims,including “any one of” the referenced claims.

Those having ordinary skill in the art will recognize that terms such as“above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are useddescriptively relative to the figures, and do not represent limitationson the scope of the invention, as defined by the claims.

Referring to the drawings, wherein like reference numbers refer to likefeatures throughout the views, FIG. 1 shows a bladder element 10 havingfeatures that provide cushioning, stability, and responsiveness. Thebladder element 10 may be for an article of footwear such as an athleticshoe, a dress shoe, a work shoe, a sandal, a slipper, a boot, or anyother category of footwear. Alternatively, the bladder element 10 couldbe used as a cushioning element in another article, such as but notlimited to a shoulder strap, a backpack, a shoulder pad, a glove, anelbow pad, a knee pad, a shin guard, or other apparel, or a sports ball.

The bladder element 10 comprises a forefoot portion 13, a midfootportion 15, and a heel portion 17. For purposes of discussion, theforefoot portion 13 is generally the forward-most third of the bladderelement 10 when worn on a foot, the midfoot portion 15 is generally themiddle third, and the heel portion 17 is generally the rearmost third.Heel portion 17 generally includes portions of the bladder element 10corresponding with rear portions of a human foot of a size correspondingwith the bladder element 10, including the calcaneus bone. Forefootportion 13 generally includes portions of the bladder element 10corresponding with the toes and the joints connecting the metatarsalswith the phalanges of the human foot of the size corresponding with thebladder element 10. Midfoot portion 15 generally includes portions ofthe bladder element 10 corresponding with an arch area of the human footof the size corresponding with the bladder element 10. Morespecifically, the bladder element 10 is referred to as a “full-length”bladder element 10 as it includes each of the forefoot portion 13, themidfoot portion 15, and the heel portion 17.

As used herein, a lateral side of a component for an article offootwear, such as a lateral side 18 of the bladder element 10 indicatedin FIG. 1, is a side that corresponds with the side of the foot of thewearer of the article of footwear that is generally further from theother foot of the wearer (i.e., the side closer to the fifth toe of thewearer). The fifth toe is commonly referred to as the little toe. Amedial side of a component for an article of footwear, such as a medialside 19 of the bladder element 10 indicated in FIG. 1, is the side thatcorresponds with an inside area of the foot of the wearer and isgenerally closer to the other foot of the wearer (i.e., the side closerto the hallux of the foot of the wearer). The hallux is commonlyreferred to as the big toe.

The bladder element 10 includes a first polymeric sheet 20, a secondpolymeric sheet 22, and a third polymeric sheet 24. As further discussedherein, and as indicated in FIG. 2, the bladder element 10 is formedfrom the three sheets 20, 22, 24 in a mold assembly 26 by thermoformingand/or vacuuforming (also referred to as vacuum forming). As indicatedin FIG. 2, the mold assembly 26 includes a first or upper mold portion26A and a second or lower mold portion 26B. The first, the second, andthe third polymeric sheets 20, 22, 24 are stacked so that they arecoextensive, and the second polymeric sheet 22 is between the firstpolymeric sheet 20 and the third polymeric sheet 24. As shown, thepolymeric sheets 20, 22, 24 are coextensive when stacked. The sheets are“coextensive” if at least the portions of the sheets that will form thefinished bladder element 10 (i.e., the portions of the sheets secured byand including the peripheral flanges 41A, 41B, 41C, not including anyportions that can be trimmed following formation of the finished bladderelement 10 of FIG. 4) are coextensive when stacked prior to formation inthe mold assembly. Because the polymeric sheets 20, 22, 24 arecoextensive, when formation of the bladder element 10 is complete, eachpolymeric sheet 20, 22, 24 contiguously extends between and forms theentire continuous peripheral flange (i.e., stacked flanges 41A, 41B,41C) discussed herein.

As indicated in FIG. 2, the second polymeric sheet 22 is formed with acontoured surface profile P prior to placement between the first andthird polymeric sheets 20, 24. For example, the second polymeric sheet22 can be thermoformed, vacuuformed, or otherwise formed to establishthe contoured surface profile P that includes a first set of surfaceportions 27 that extend in a first direction toward the first polymericsheet 20, and a second set of surface portions 28 positioned between thesurface portions 27, that extend in an opposite second direction towardthe third polymeric sheet 24. Stated differently, the surface portions27 on a first surface 30 of the second polymeric sheet 22 are thoseportions of the second polymeric sheet 22 that extend furthest toward aninner surface 32 of the first polymeric sheet 20. The surface portions28 on a second surface 34 of the second polymeric sheet 22 are thoseportions of the second polymeric sheet 22 that extend furthest toward aninner surface 36 of the third polymeric sheet 24.

In contrast, the first and third polymeric sheets 20, 24 may besubstantially flat sheets without contoured surfaces (i.e., with planarsurfaces) when initially placed in the mold assembly 26, prior to thethermoforming and vacuum forming in the mold assembly 26. For example,the sheets 20, 24 may be cut so that the perimeters of the sheets 20, 24have contoured curves, but the surfaces of the sheets 20, 24 aregenerally flat prior to forming on the mold assembly 26. The surfaces ofthe sheets 20, 24 may take on contoured shapes of the mold surfaces 40A,40B when a vacuum is applied through a plurality of conduits 38 in themold assembly 26 to conform the first polymeric sheet 20 to the moldsurface 40A of the first mold portion 26A, and to conform the thirdpolymeric sheet 24 to a mold surface 40B of the second mold portion 26B.Any or all of the polymeric sheets 20, 22, 24 may be preheated prior toplacement in the mold assembly 26 to increase the formability of thesheets 20, 22, 24, and the ability of the sheets 20, 22, 24 to thermallybond to one another as discussed herein.

Various additional conduits in the mold assembly 26 also enable fluidcommunication with internal chambers within the bladder element 10 thatare bounded at least partially by the second polymeric sheet 22 when themold assembly 26 is in the closed position of FIG. 3. Such fluidconduits may be generally perpendicular to the cross-sectional views ofFIGS. 2 and 3. For example, the mold surface 40A may have conduits 42Aspaced along a perimeter of the mold surface 40A, and the mold surface40B may have conduits 42B spaced along a perimeter of the mold surface40B. When the first and third polymeric sheets 20, 24 are pulled againstthe mold surfaces 40A, 40B by the vacuum, small fill tubes are formed bythe sheets 20, 24 at the conduits 42A, 42B, allowing fluid communicationinto chambers formed between the sheets 20, 22, and into chambers formedbetween the sheets 22, 24, as discussed herein.

When the mold assembly 26 is closed as shown in FIG. 3, fluid pressurecan be introduced into the mold assembly 26 through the conduits 42A,such that the fluid pressure is applied to the first surface 30 of thesecond polymeric sheet 22. The fluid pressure on the first surface 30forces the surface portions 28 of the second surface 34 of the secondpolymeric sheet 22 into contact with the inner surface 36 of the thirdpolymeric sheet 24.

Similarly, fluid pressure can be introduced into the mold assembly 26through the conduits 42B, such that the fluid pressure is applied to thesecond surface 34 of the second polymeric sheet 22. The fluid pressureon the second surface 34 forces the surface portions 27 of the firstsurface 30 of the second polymeric sheet 22 into contact with the innersurface 32 of the first polymeric sheet 20. In other embodiments,depending on the desired configuration of the bladder element, fluidpressure may be applied only between the first and second polymer sheets20, 22, or may be applied only between the second and third polymericsheets 22, 24. FIG. 3 shows arrows A representing fluid pressureintroduced through conduits 42B forcing portions 27 of the first surface30 against the inner surface 32, and shows arrows B representing fluidpressure introduced through conduits 42A forcing portions 28 of thesecond surface 34 against the inner surface 36.

Heat in the mold assembly 26 combined with the fluid pressure causes thesecond polymeric sheet 22 to be secured to the first polymeric sheet 20by thermally bonding to the first polymeric sheet 20 at the portions 27forced into contact with the inner surface 32, and to be secured to thethird polymeric sheet 24 by thermally bonding to the third polymericsheet 24 at the portions 28 forced into contact with the inner surface36. The first polymeric sheet 20 is thus tethered to the third polymericsheet 24 by the second polymeric sheet 22.

FIG. 1 shows a first peripheral flange 41A at a first perimeter P1 ofthe first polymeric sheet 20, a second peripheral flange 41B at a secondperimeter P2 of the second polymeric sheet 22, and a third peripheralflange 41C at a third perimeter P3 of the third polymeric sheet 24. Asshown in FIGS. 2-4, the flanges 41A, 41B, 41C are stacked so that thefirst peripheral flange 41A rests on the second peripheral flange 41B,and the second peripheral flange 41B rests on the third peripheralflange 41C. When heat and compression are applied by the mold assembly26, the flange 41A is secured to the flange 41B, and the flange 41B issecured to the flange 41C so that the peripheral flanges 41A, 41B, 41Cform a continuous peripheral flange that surrounds the bladder element10. The first polymeric sheet 20 and the third polymeric sheet 24 aresecured only to the second polymeric sheet 22 and not directly to oneanother, but they are tethered to one another by the second polymericsheet 22. Adhesive and/or radio frequency welding may be used in someembodiments to secure the flanges 41A, 41B, 41C as described. Theflanges 41A, 41B, 41C can be trimmed after the bladder element 10 isremoved from the mold assembly 26, as shown in FIG. 4.

With reference to FIG. 4, after formation in the mold assembly 26, thebladder element 10 has a first fluid chamber 46A that comprises a volumebounded by the first polymeric sheet 20 and the second polymeric sheet22. The bladder element 10 also has a second fluid chamber 46B thatcomprises a volume bounded by the second polymeric sheet 22 and thethird polymeric sheet 24. The first fluid chamber 46A is not in fluidcommunication with the second fluid chamber 46B. In other words, thesecond polymeric sheet 22 isolates the first fluid chamber 46A from thesecond fluid chamber 46B.

Additionally, the second polymeric sheet 22 is configured so that athird fluid chamber 46C comprises a volume bounded by the firstpolymeric sheet 20 and the second polymeric sheet 22, and a fourth fluidchamber 46D comprises a volume bounded by the second polymeric sheet 22and the third polymeric sheet 24. The first fluid chamber 46A is extendsover (i.e., is above) the second fluid chamber 46B in the heel portion17, and the third fluid chamber 46C and the fourth fluid chamber 46D areadjacent one another in the forefoot portion 13, with the fourth fluidchamber 46D forward of the third fluid chamber 46C. Stated differently,the chambers 46C and 46D are side-by-side, and not vertically stackedrelative to one another. The third fluid chamber 46C and the fourthfluid chamber 46D are not in fluid communication with the first fluidchamber 46A, with the second fluid chamber 46B, or with one another. Inother words, the second polymeric sheet 22 isolates the third fluidchamber 46C from the fourth fluid chamber 46D, and from the first andsecond fluid chambers 46A, 46B. The contoured surface profile P of thesecond polymeric sheet 22 enables this isolation of the fluid chambersand tethering of the first and third polymeric sheets 20, 24.

The same fill tubes formed by the polymeric sheets 20, 24 at the variousconduits 42A, 42B can be used to inflate one or more of the fluidchambers 46A-46D, and then can be sealed to retain the fluid in thechambers. For example, in the embodiment of FIG. 4, the first fluidchamber 46A is inflated to a first predetermined pressure, and thesecond fluid chamber 46B is inflated to a second predetermined pressurethat may be different from the first predetermined pressure.Additionally, the third fluid chamber 46C is inflated to a thirdpredetermined pressure that may be different from the first or thesecond predetermined pressures, or both. The fourth fluid chamber 46Dmay also be inflated to a fourth predetermined pressure that may bedifferent from any of all of the first, the second, or thirdpredetermined pressures. In other words, at least one of the firstpredetermined pressure, the second predetermined pressure, the thirdpredetermined pressure, and the fourth predetermined pressure differsfrom another of the first predetermined pressure, the secondpredetermined pressure, the third predetermined pressure, and the fourthpredetermined pressure. The bladder element 10 also has additional fluidchambers 46E, 46F, 46G that are each isolated from the other fluidchambers by the second polymeric sheet 22. Any or all of theseadditional fluid chambers 46E, 46F, 46G can be inflated to respectivepredetermined pressures that are different from predetermined pressuresin one or more of the other fluid chambers. As shown in FIGS. 1 and 4,the polymeric sheets 20, 22, 24 are relatively flat in the heel portion17. In fact, the entire first polymeric sheet 20 and third polymericsheet 24 are relatively flat in comparison to the second polymeric sheet22 due to the preformed, contoured surface profile P of the secondpolymeric sheet 22, and the shape of the inner surfaces 40A, 40B of themold assembly 60. In another embodiment, the first polymeric sheet 20and the third polymeric sheet 24 could also each be formed with arespective contoured surface profile even prior to placement in the moldassembly 26 and application of fluid pressure thereto, so that each ofthe polymeric sheets 20, 22, 24 has a respective contoured surfaceprofile, each of which can be different from one another.

Under the method, a pressure map of pressures applied during weartesting of a test article of footwear can be determined. The weartesting may be performed over a plurality of wearers, with the pressuremap being a population average of the applied pressures of the testedwearers, or the pressure map may be of the applied pressures of only aparticular wearer. In the latter case, the predetermined inflationpressures and resulting cushioning response of the bladder element 10are thus customized to the particular wearer.

For example, the pressures applied in a corresponding forefoot portion13, midfoot portion 15, and heel portion 17 during wear of a test pairof an article of footwear can be monitored and determined. The articleof footwear may have the bladder element 10 or 110, or may be adifferent article of footwear. An example of a pressure map 49 is shownin FIG. 11. The pressure map 49 shows various zones Z1, Z2, Z3, and Z4.Each zone Z1, Z2, Z3, and Z4 corresponds to a range of magnitudes ofpressures experienced in the various portions 13, 15, 17. Zone Z1represents a first range of magnitudes of pressures. Zone Z2 representsa second range of magnitudes of pressures less than the first range.Zone Z3 represents a third range of magnitudes of pressures less thanthe second range. Zone Z4 represents a fourth range of magnitudes ofpressures less than the third range. At least some of the fluid chambers46A-46F can be inflated to and can maintain predetermined pressures thatare selected based on the pressure values of corresponding pressureZones Z1-Z4. For example, the pressures in Zones Z1, Z2, and Z3 in theheel region 17 and in the forefoot region 13 are generally higher thanthe pressures in Zone Z4 in the midfoot 15. Fluid chambers 46A, 46B, 46Dand 46G generally correspond to Zones Z1, Z2, and Z3 in the heel region17 and in the forefoot region 13, and fluid pressures within thosechambers may be selected to be higher than in the fluid chambers 46E,46F, and 46G.

As used herein, a “fluid” includes a gas, including air, an inert gassuch as nitrogen, or another gas. Accordingly, “fluid-filled” includes“gas-filled”. The fluid used to force the second polymeric sheet 22against the inner surfaces 32, 36, respectively, of the first and thirdpolymeric sheets 20, 24 may be the same fluid that is used to inflatethe chambers 46A-46G and which is then sealed in the chambers 46A-46G,or may be a different fluid. For example, air may be used to force thesecond polymeric sheet 22 against the inner surfaces 32, 36 of the firstand third polymeric sheets 20, 24, but then the chambers 46A-46G may befilled and pressurized with another gas, and then the fill tubes can besealed.

The various materials used for the bladder element 10, and otherembodiments of bladder elements discussed herein, may be substantiallytransparent. As used herein, a component is “substantially transparent”if it has a luminous transmittance (i.e., a percentage of incident lightthat is transmitted) of at least 80 percent and haze (i.e., percentageof transmitted light that is scattered) of not more than 56 percent.Those skilled in the art will readily understand a variety of methods todetermine luminous transmittance and haze of an object, such as thebladder element 10. Additionally, in some embodiments, the bladderelement 10 may have a tinted color.

The fluid-filled bladder element 10 and other embodiments of bladderelements described herein can be formed from a variety of polymericmaterials. For example, the bladder element 10 can be formed from any ofvarious polymeric materials that can retain a fluid at a predeterminedpressure, including a fluid that is a gas, such as air, nitrogen, oranother gas. For example, the bladder element 10 can be a thermoplasticpolymeric material. The bladder element 10 can be a urethane,polyurethane, polyester, polyester polyurethane, and/or polyetherpolyurethane.

Moreover, any or all of the polymeric sheets 20, 22, 24 used to form thebladder element 10 or other embodiments of bladder elements describedherein can each in turn be formed of one or more sheets having layers ofdifferent materials. FIG. 10, which is a close-up, cross-sectionalportion of the bladder element 10 taken at the cross-section shown inFIG. 1, shows that the bladder element 10 is a laminate membrane formedfrom thin films having one or more first layers 50A that comprisethermoplastic polyurethane layers and that alternate with one or moresecond layers 50B, also referred to herein as barrier layers, gasbarrier polymers, or gas barrier layers, that comprise a copolymer ofethylene and vinyl alcohol (EVOH) that is impermeable to the pressurizedfluid contained therein as disclosed in U.S. Pat. No. 6,082,025 to Bonket al., which is incorporated by reference in its entirety. The secondand third polymeric sheets 22, 24 may be formed from the same materialsshown and described in FIG. 10 with respect to the first polymeric sheet20. The first layer 50A may be arranged to form an outer surface of thefirst polymeric sheet 20. That is, the outermost (top) first layer 50Ashown in FIG. 10 may be the outer surface of the fluid-filled bladderelement 10. The fluid-filled bladder element 10 may also be formed froma material that includes alternating layers of thermoplasticpolyurethane and ethylene-vinyl alcohol copolymer, as disclosed in U.S.Pat. Nos. 5,713,141 and 5,952,065 to Mitchell et al. which areincorporated by reference in their entireties. Alternatively, the layersmay include ethylene-vinyl alcohol copolymer, thermoplasticpolyurethane, and a regrind material of the ethylene-vinyl alcoholcopolymer and thermoplastic polyurethane. The bladder element 10 mayalso be a flexible microlayer membrane that includes alternating layersof a gas barrier polymer material such as second layers 50B and anelastomeric material such as first layers 50A, as disclosed in U.S. Pat.Nos. 6,082,025 and 6,127,026 to Bonk et al. which are incorporated byreference in their entireties. With such alternating layers, forexample, the bladder element 10 or any of the additional bladderelements described herein may have a gas transmission rate for nitrogenof less than 10 cubic centimeters per square meter per atmosphere perday, or of less than 1 cubic centimeter per square meter per atmosphereper day. Additional suitable materials for the bladder element 10 aredisclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy which areincorporated by reference in their entireties. Further suitablematerials for the bladder element 10 include thermoplastic filmscontaining a crystalline material, as disclosed in U.S. Pat. Nos.4,936,029 and 5,042,176 to Rudy, and polyurethane including a polyesterpolyol, as disclosed in U.S. Pat. Nos. 6,013,340, 6,203,868, and6,321,465 to Bonk et al. which are incorporated by reference in theirentireties. In selecting materials for the bladder element 10,engineering properties such as tensile strength, stretch properties,fatigue characteristics, dynamic modulus, and loss tangent can beconsidered. The thicknesses of the first, second, and third polymericsheets 20, 22, 24 of materials used to form the bladder element 10 canbe selected to provide these characteristics.

Next, the bladder element 10 can be secured to an upper either directlyor indirectly. One embodiment of an upper 160 is shown in FIG. 5. Theupper 160 can be secured to the bladder element 10 by various methods,such as adhesives, stitching, a combination of these methods, orotherwise. The upper 160 can include a strobel unit that can overlay andbe adhered to the upper surface bladder element. Alternatively, thebladder element 10 can be secured to the upper 160 indirectly, such asvia a midsole layer (not shown). The midsole layer may be an ethylenevinyl acetate (EVA) foam, or other type of cushioning material, that isin turn secured to the upper 160.

An outsole, such as an outsole 162 shown in FIGS. 5 and 6, may then besecured to the bladder element 10. The outsole 162 can be a single,continuous, integral component that covers the entire ground-facingsurface of the bladder element 10. Alternatively, discrete outsoleelements can be secured at different areas of the ground-facing surfaceof the bladder element 10. The outsole 162 can be a high wear material,such as a durable rubber.

FIGS. 5 and 6 show another embodiment of a bladder element 110 includedin an article of footwear 112 that may be formed according to the samemethod described with respect to FIG. 1. The bladder element 110 isformed from a first polymeric sheet 120, a second polymeric sheet 122,and a third polymeric sheet 124. The second polymeric sheet 122 isformed to have a contoured surface profile P10, even prior to placingthe sheets 120, 122, 124 in a mold assembly similar to mold assembly 26.The first polymeric sheet 120, the second polymeric 122, and the thirdpolymeric sheet 124 are stacked in the mold assembly so that the threesheets are co-extensive and the second polymeric sheet 122 is betweenthe first polymeric sheet 120 and the third polymeric sheet 124. Morespecifically, a flange 141A at a perimeter of the first polymeric sheet120 is secured to a flange 141B at a perimeter of the second polymericsheet 122, and the flange 141B is secured to the flange 141C of thethird polymeric sheet 124. Fluid pressure is applied between the firstpolymeric sheet 120 and second polymeric sheet 122, between the secondpolymeric sheet 122 and the third polymeric sheet 124, or between both,to force a first surface 130 of the second polymeric sheet 122 intocontact with an inner surface 132 of the first polymeric sheet 120, anda second surface 134 of the second polymeric sheet 122 into contact withan inner surface 136 of the third polymeric sheet 124 (as shown in FIG.6). The second polymeric sheet 122 is then secured to the first andthird polymeric sheets 122, 124 by thermal bonding at those portionsforced into contact with one another by fluid pressure. No anti-weldingmaterial is used or required between any of the first, second, and thirdpolymeric sheets 120, 122, 124. The stacked flanges 141A, 141B, 141C ofthe polymeric sheets 120, 122, 124 are secured to one another by thermalbonding, compression, adhesives, or RF welding to form a continuousperipheral flange and the bladder element 110. The first polymeric sheet120 and the third polymeric sheet 124 are secured only to the secondpolymeric sheet 122 and not directly to one another. They are tetheredto one another by the second polymeric sheet 122.

In the embodiment of FIGS. 5 and 6, the contoured surface profile P10 ofthe second polymeric sheet 122 creates channels 164 that interconnectthe fluid chambers 146A, 146B, 146C, 146D, 146E, 146F, and 146G formedby and between the first polymeric sheet 120 and the second polymericsheet 122. Each of the chambers 146A-146G is a respective volume boundedby the first polymeric sheet 120 and the second polymeric sheet 122.Because the fluid chambers 146A-146G can be in fluid communication withone another by the channels 164, all of the fluid chambers 146A-146G areat the same fluid pressure. In other words, the chambers 146A-146G canbe inflated to a predetermined pressure through one or more conduitssimilar to any of the conduits 42A of FIG. 1, with the conduit orconduits then sealed, and all fluid chambers 146A-146G will then be atthe same predetermined pressure. Alternatively, each of the chambers146A-146G can be inflated individually, with the adjacent channel 164then plugged, so that some or all of the chambers 146A-146G can beinflated to and can maintain different predetermined fluid pressures.The fluid pressures of the chambers 146A-146G may be selected based onthe pressure map 49 as described with respect to the bladder element 10.

As shown in FIG. 6, the second polymeric sheet 122 does not extendcompletely to the inner surface 136 of the third polymeric sheet 124 atthe lateral side 118 and the medial side 119, as evidenced by the fluidchambers 146L between the third polymeric sheet 124 and the secondpolymeric sheet 122 at the cross-section shown. If the contoured profileP10 of the second polymeric sheet 122 is formed in a like manner as this(i.e., not extending completely from the lateral side 118 to the medialside 119) from the forefoot region 13 to the heel region 17, then eachof the fluid chambers 146H-146O formed by and between the secondpolymeric sheet 122 and the third polymeric sheet 124 will be in fluidcommunication with one another at the same fluid pressure. Each of thechambers 146H-146O is a volume bounded by the second polymeric sheet 122and the third polymeric sheet 124. Because the chambers 146H-146O are influid communication with one another, the chambers 146H-146O can beinflated to a predetermined pressure through one or more conduitssimilar to any of the conduits 42B of FIG. 1, with the conduit orconduits then sealed, and all fluid chambers 146H-146O will then be atthe same predetermined pressure, which may be different than thepredetermined pressure of the fluid chambers 146A-146G.

FIGS. 7-9 show another embodiment of a bladder element 210 which can beincluded in an article of footwear. The bladder element 210 is formedfrom a first polymeric sheet 220, a second polymeric sheet 222, and athird polymeric sheet 224. The second polymeric sheet 222 is formed witha contoured surface profile P14. The third polymeric sheet 224 is formedto have a cavity 268 having an open side 270. The first and secondpolymeric sheets 220, 222 are formed separately from the third polymericsheet 224, and are bonded to one another to enclose a plurality of fluidchambers 246A, 246B, 246C, 246D, and 246E that are fluidly connectedwith one another by channels 264 formed by the second polymeric sheet222.

As indicated, the second polymeric sheet 222 is bonded to the firstpolymeric sheet 220 and is formed to have a contoured surface profileP14, including formed protrusions 228, even prior to placing the secondpolymeric sheet 222 to extend into the cavity 268 as indicated in FIG.8. When positioned to extend into the cavity 268, the second polymericsheet 222 is entirely in the cavity 268 and enclosed therein by thefirst polymeric sheet 220 and the third polymeric sheet 224 when thefirst polymeric sheet 220 covers the open side 270. The first polymericsheet 220 and second polymeric 222 are stacked on the third polymericsheet 224 in a mold assembly similar to mold assembly 26, so that thethree sheets are co-extensive and the second polymeric sheet 222 isbetween the first polymeric sheet 220 and the third polymeric sheet 224.More specifically, a flange 241A at a perimeter of the first polymericsheet 220 is stacked on a flange 241B at a perimeter of the secondpolymeric sheet 222, and the flange 241B is stacked on a flange 241C ofthe third polymeric sheet 224. Fluid pressure is applied between thefirst polymeric sheet 220 and second polymeric sheet 222, between thesecond polymeric sheet 222 and the third polymeric sheet 224, or betweenboth, to force a surface 234 of the second polymeric sheet 222 intocontact with an inner surface 236 of the third polymeric sheet 224. Thesecond polymeric sheet 222 is then secured to the first and thirdpolymeric sheets 222, 224 by thermal bonding at those portions of theformed protrusions 228 that are forced into contact with the thirdpolymeric sheet 224 by fluid pressure that can be introduced throughconduits similar to conduits 42B of FIG. 1. No anti-welding material isused or required between any of the first, second, and third polymericsheets 220, 222, 224. The stacked peripheral flanges 241A, 241B, 241C ofthe polymeric sheets 220, 222, 224 are secured to one another by thermalbonding, compression, adhesives, or RF welding so that the peripheralflanges 241A, 241B, 241C form a continuous peripheral flange around thebladder element 210. The first polymeric sheet 220 and the thirdpolymeric sheet 224 are secured only to the second polymeric sheet 222and not directly to one another, but are tethered to one another by thesecond polymeric sheet 222.

In the embodiment of FIGS. 7-9, the contoured surface profile P14 of thesecond polymeric sheet 222 includes channels 264 that interconnect thefluid chambers 246A, 246B, 246C, 246D, 246E, 246F, 246G, 246H, 246I,246J formed by and between the first polymeric sheet 220 and the secondpolymeric sheet 222. Each of the chambers 246A-246J is a volume boundedby the first polymeric sheet 220 and the second polymeric sheet 222.Because the fluid chambers 246A-246J are in fluid communication with oneanother by the channels 264, all of the fluid chambers 246A-246J are atthe same fluid pressure. In other words, the chambers 246A-246J can beinflated to a predetermined pressure through one or more conduitssimilar to any of the conduits 42A of FIG. 1, with the conduit orconduits then sealed, and all fluid chambers 246A-246J will then be atthe same predetermined pressure. Alternatively, each of the chambers246A-246J can be inflated individually, with the adjacent channel 264then plugged, so that some or all of the chambers 246A-246J can beinflated to and can maintain different predetermined fluid pressures.The fluid pressures of the chambers 246A-246J may be selected based onthe pressure map 49 as described with respect to the bladder element 10.

As shown in FIG. 8, the second polymeric sheet 222 does not extendcompletely to the inner surface 236 of the third polymeric sheet 224 atthe lateral side 218 and the medial side 219. Additionally, the secondpolymeric sheet 222 forms spaces 229 (i.e., voids) surrounding each ofthe protrusions 228 and that form a continuous volume around theprotrusions 228 between the second polymeric sheet 222 and the thirdpolymeric sheet 224. The spaces 229 are in fluid communication with oneanother. The third polymeric sheet 224 is vacuuformed and/orthermoformed in a mold assembly similar to mold assembly 26 to have acontoured surface profile with protrusions 274 that extend toward theprotrusions 228 of the second polymeric sheet 222 when the secondpolymeric sheet 222 is positioned in the mold assembly 26 to extend intothe cavity 268. The protrusions 274 contact the protrusions 228 so thatthe surface 234 thermally bonds to the inner surface 236.

The continuous volume around the protrusions 228 between the secondpolymeric sheet 222 and the third polymeric sheet 224 (i.e., the volumeof the spaces 229) can be inflated to a predetermined pressure throughone or more conduits similar to any of the conduits 42B of FIG. 1, withthe conduit or conduits then sealed, and the volume between the secondand third polymeric sheets 222, 224 will then be at the samepredetermined pressure, which may be different than the predeterminedpressure(s) of the fluid chambers 246A-246J.

While several modes for carrying out the many aspects of the presentteachings have been described in detail, those familiar with the art towhich these teachings relate will recognize various alternative aspectsfor practicing the present teachings that are within the scope of theappended claims. It is intended that all matter contained in the abovedescription or shown in the accompanying drawings shall be interpretedas illustrative only and not as limiting.

What is claimed is:
 1. A method of manufacturing a bladder elementcomprising: forming at least one of a first polymeric sheet, a secondpolymeric sheet, or a third polymeric sheet with a contoured surfaceprofile; after said forming, stacking the first polymeric sheet, thesecond polymeric sheet, and the third polymeric sheet in a mold assemblyso that the second polymeric sheet is between the first polymeric sheetand the third polymeric sheet; and applying fluid pressure in the moldassembly: between the second polymeric sheet and the third polymericsheet, forcing a first surface of the second polymeric sheet intocontact with an inner surface of the first polymeric sheet, or betweenthe first polymeric sheet and second polymeric sheet, forcing a secondsurface of the second polymeric sheet into contact with an inner surfaceof the third polymeric sheet, or between the first polymeric sheet andsecond polymeric sheet, and between the second polymeric sheet and thethird polymeric sheet, forcing both the second surface of the secondpolymeric sheet into contact with the inner surface of the thirdpolymeric sheet, and the first surface of the second polymeric sheetinto contact with the inner surface of the first polymeric sheet.
 2. Themethod of claim 1, wherein said forming is by thermoforming.
 3. Themethod of claim 1, further comprising: securing a flange at a perimeterof at least one of the first polymeric sheet, the second polymericsheet, and the third polymeric sheet, to a flange at a perimeter ofanother of the first polymeric sheet, the second polymeric sheet, andthe third polymeric sheet by at least one of compression,radio-frequency welding, thermal bonding, or adhesive.
 4. The method ofclaim 1, wherein said forming configures the first polymeric sheet andthe second polymeric sheet so that: a first fluid chamber comprises avolume bounded by the first polymeric sheet and the second polymericsheet; a second fluid chamber comprises a volume bounded by the secondpolymeric sheet and the third polymeric sheet; and the method furthercomprising: inflating at least one of the first fluid chamber or thesecond fluid chamber.
 5. The method of claim 4, wherein the first fluidchamber is isolated from the second fluid chamber, and said inflatingcomprises inflating the first fluid chamber to a first predeterminedpressure, and inflating the second fluid chamber to a secondpredetermined pressure.
 6. The method of claim 5, wherein: said formingconfigures the second polymeric sheet so that a third fluid chambercomprises a volume bounded by the first polymeric sheet and the secondpolymeric sheet, and a fourth fluid chamber comprises a volume boundedby the second polymeric sheet and the third polymeric sheet; the thirdfluid chamber and the fourth fluid chamber are isolated from the firstfluid chamber, from the second fluid chamber, or from one another; saidinflating comprises inflating the third fluid chamber to a thirdpredetermined pressure, and the fourth fluid chamber to a fourthpredetermined pressure; and at least one of the first predeterminedpressure, the second predetermined pressure, the third predeterminedpressure, and the fourth predetermined pressure differs from another ofthe first predetermined pressure, the second predetermined pressure, thethird predetermined pressure, and the fourth predetermined pressure. 7.The method of claim 6, further comprising: securing the bladder elementto an article of footwear; wherein the bladder element comprises atleast one of a forefoot portion, a midfoot portion, and a heel portion.8. The method of claim 7, wherein: the bladder element comprises aforefoot portion, a midfoot portion and a heel portion; the first fluidchamber extends over the second fluid chamber in the heel portion; andthe third fluid chamber and the fourth fluid chamber are adjacent oneanother in the forefoot portion.
 9. The method of claim 5, furthercomprising: monitoring pressures applied to an article of footwearduring wear testing; and selecting at least some of the predeterminedpressures based on the pressures applied.
 10. The method of claim 1,wherein: the mold assembly is a thermoforming and/or vacuuforming moldassembly; said forming is thermoforming and/or vacuuforming; and furthercomprising securing: the first surface of the second polymeric sheet tothe inner surface of the first polymeric sheet, and the second surfaceof the second polymeric sheet to the inner surface of the thirdpolymeric sheet while the second polymeric sheet, the first polymericsheet, and the third polymeric sheet are in the mold assembly.
 11. Themethod of claim 10, wherein said securing is with: the first polymericsheet and the second polymeric sheet free of anti-welding material, orthe second polymeric sheet and the third polymeric sheet free ofanti-welding material, or the first polymeric sheet, the secondpolymeric sheet, and the third polymeric sheet free of anti-weldingmaterial.
 12. The method of claim 10, wherein: said forming at least oneof the first polymeric sheet, the second polymeric sheet, or the thirdpolymeric sheet with a contoured surface profile comprises forming thesecond polymeric sheet with the contoured surface profile; and saidsecuring the first surface of the second polymeric sheet to the innersurface of the first polymeric sheet and the second surface of thesecond polymeric sheet to the inner surface of the third polymeric sheettethers the first polymeric sheet to the third polymeric sheet.
 13. Themethod of claim 1, wherein said forming at least one of the firstpolymeric sheet, the second polymeric sheet, or the third polymericsheet with a contoured surface profile comprises forming each of thefirst polymeric sheet, the second polymeric sheet, and the thirdpolymeric sheet with a respective contoured surface profile.
 14. Themethod of claim 1, wherein: said forming comprises forming the thirdpolymeric sheet with a cavity comprising an open side; and the secondpolymeric sheet extends into the cavity from the open side.
 15. Themethod of claim 1, wherein: said forming at least one of the firstpolymeric sheet, the second polymeric sheet, or the third polymericsheet with a contoured surface profile comprises forming the secondpolymeric sheet so that the second polymeric sheet at least partiallydefines a plurality of fluid chambers between the first polymeric sheetand the third polymeric sheet; and at least some of the plurality offluid chambers are isolated from one another by the second polymericsheet.